Protein Therapeutic Research and Development: A Growing Role for the DMPK Scientist Jerry Galluppi Director, DMPK Biogen Idec
D M P K
Presentation Outline: •Definitions, Background Information •The R&D process: � Discovery, Lead Identification � Preclinical Development � Clinical Development •NDA Approval, Labeling •Life-Cycle Management •Summary Comments
R What is a protein? _ H 2 N-C-COH = _ H O amino acid •A protein is a biopolymer made of amino acids joined end to end •There are 20 kinds of amino acids (differing in structure at the R group), the sequence of which are encoded by: translation transcription DNA RNA protein sequence R 1 R 2 R 3 R 4 R 5 R n _ _ _ _ _ _ H 2 N-C-C-N-C-C-N-C-C-N-C-C-N-C-C-……….N-C-COH = = = = = = _ _ _ _ _ _ H O H O H O H O H O H O
What is a protein? Proteins perform a wide variety of biological functions: •Enzymes (catalyze reactions) •Enzyme inhibitors/modulators •Carriers of small molecules •Mediators – hormones •Receptors/Signaling •Antibodies •Cellular structure components •Many other functions
Monoclonal Antibodies (substantial variety in specificity, many common features in physical properties)
Non-Monoclonal Antibodies (substantial variety in size, structure, and other chemical and biological properties) • Blood Factor VIII: up to 200k (glycoprotein) • Cytokines: 10-70k (interferons, EPO, etc) • Insulin: 5.8k, two chains (some assembly required) • Dipeptides or even single amino acids can have potent bioactivity MSG One of the 20 natural amino acids
•Proteins can undergo natural post-translational modification: � Large carbohydrate moieties attached (glycosylation) � Phosphorylation � Sulfation � N or C-terminal modifications � Proteolytic processing � Over 40 other modifications have been identified •If such modifications are required for activity, the means of production by genetically engineered cells may be limited – for example, engineered E. coli cells will not glycoslyate proteins •In addition, bioprocess engineers and chemists can chemically modify peptides (peptidomimetics) and proteins in the laboratory to improve pharmaceutical properties such as solubility, stability, activity, safety, and others (for example, polyethylene glycol (PEG) conjugates) Bottom line – All “pure” protein preparations are actually mixtures with varying degrees of micro-heterogeneity
Drug R&D “stages” and the role of the DMPK Scientist
Data Driven Decisions vs Guessing Do you feel lucky, Punk? A team informed by data
The “good” old days of drug R&D Discovery Preclinical Clinical •Toxicology/pathology •Chemistry •Clinical pharmacology •ADME/PK •Pharmacology •Trial design •Pharmaceutical science •Molecular biology •Clinical statistics •Process development •Cell biology Input from Business Development, Regulatory Affairs, Project Management
The new paradigm for drug R&D • Integration of skills • Joint ownership/responsibility Discovery Preclinical Clinical Input from Business Development, Regulatory Affairs, Project Management
The new paradigm for drug R&D • Integration of skills • Joint ownership/responsibility Discovery Preclinical Clinical Input from Business Development, Regulatory Affairs, Project Management, Patent
New Target Generic Candidate High throughput chem/phys, Testing Scheme ADME, and safety screening: HITS • In silico – rule of 5, clogP • DEREK/TOPKAT • ID/Purity/stability Med Chem SAR Set The Goal : • Solubility ( in vitro potency Pre-determine a target • Pharmaceutical properties and selectivity) candidate profile based • Electrophilicity upon the following: • Metabolic stability • Permeability/Efflux •Efficacy • Protein binding in vivo PK in PD species •Selectivity (BA, CL, V, t 1/2 ) •ADME •Safety •Pharmaceutical Lower throughput ADME/safety tests: PD proof of efficacy •Ease of synthesis • CL mechanism(s) in one or more species •Other properties • Metabolite profiling • Metabolite ID • In vitro in vivo prediction PK/PD, TK/TD • Cross species comparison evaluation • P450 inhibition/characterization • Safety profiling in vitro DOES THE CANDIDATE MEET ALL THE CRITERIA?? • Safety issues resolution Multi-species • Allometric scaling, PBPK ADME/safety
New Target Generic Candidate High throughput chem/phys, Testing Scheme ADME, and safety screening: HITS • In silico – rule of 5, clogP • DEREK/TOPKAT • ID/Purity/stability Med Chem SAR Set The Goal: • Solubility ( in vitro potency Pre-determine a target • Pharmaceutical properties and selectivity) candidate profile based • Electrophilicity upon the following: • Metabolic stability • Permeability/Efflux •Efficacy • Protein binding in vivo PK in PD species •Selectivity (BA, CL, V, t 1/2 ) •ADME •Safety •Pharmaceutical Lower throughput ADME/safety tests: PD proof of efficacy •Ease of synthesis • CL mechanism(s) in one or more species •Other properties • Metabolite profiling • Metabolite ID • In vitro in vivo prediction PK/PD, TK/TD • Cross species comparison evaluation • P450 inhibition/characterization • Safety profiling in vitro DOES THE CANDIDATE MEET ALL THE CRITERIA?? • Safety issues resolution Multi-species • Allometric scaling, PBPK ADME/safety
Integrated R&D model has shifted the reasons why drug candidates fail in development – fewer failures due to poor ADME properties largely due to better screening pre-R2D R. Boyd, R. Lalonde Clinical Pharmacology and Therapeutics January 2007
Why do we need to make better use of pharmacometrics? New *PDUFA rules to clear backlogs *PDUFA: prescription drug user fee act Bernard Munos Nature Reviews/Drug Discovery December 2009
Why do we need to make better use of pharmacometrics? Waning productivity in drug R&D is not a new observation. There have been a number of innovative attempts to improve R&D output including: •Investment in science and technology - •Recombinant DNA technology/Site-directed mutagenesis •Hybridomas •Genomics (genomics, proteomics, metabolomics, you-name-it-omics) •Gene knockouts •Expanded chemical diversity •High throughput screening •etc •Partnerships and consortia to de-risk and/or synergize expertise •Mergers and Acquistions (bigger is better…….NOT!) •Shift from bucket brigade to functionally integrated R&D teams
Why do we need to make better use of pharmacometrics? New *PDUFA rules to clear backlogs *PDUFA: prescription drug user fee act Bernard Munos Nature Reviews/Drug Discovery December 2009
Bernard Munos Nature Reviews/Drug Discovery December 2009 Sounds a lot like:
How Do We Improve? Drug Co B Drug Co D Drug Co C Drug Co E Drug Co A http://www.fda.gov/oc/initiatives/criticalpath/stanski/stanski.html
DMPK Role in Discovery Research: •Identify strong development candidates based on quantitative criteria (Product Candidate Criteria – eg. Acceptable BA, sufficient PK to drive response safely , etc. ) •Provide critical information to the development team regarding clinical dosing strategy based on early PK/PD, formulation, choice of route, device, biomarkers (good and bad), populations (what to expect in humans) The Discovery period for a biological candidate is about the same as that for a small molecule – about 1-3 years
DMPK Role in Process and Formulation Development •Select final formulation for preclinical safety and clinical evaluation • Must support systemic exposure requirements •Protein therapeutic agents are always heterogeneous (contain by- products of both the fermentation and purification process). Assessing the impact of contaminants and defining release specifications is challenging especially as process and/or formulation changes are made during scale up • Defining comparability/bioequivalence involves PK/PD analysis •Hitting commercially feasible cost-of-goods targets can be an issue for products requiring high dose levels • Crucial to “tailor” dose strategy (not overdose, choose the right population)
DMPK Role in Preclinical Research: •Assess toxicokinetics to support safety studies •Evaluate anti-drug antibody formation and impact on bioactivity (ADA) •Perform allometric scaling to human PK •Further refine PK/PD understanding, including site of action distribution, clearance pathways, linearity •Begin thinking about drug-drug interaction strategy (yes, I said drug-drug interactions!) •Begin thinking about special populations, eg. renal insufficiency, pediatrics, etc.
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